I have two betta fish, a crowntail and one that I forget what it's called. Anyway, I have them in a 2.5 gallon tank with colorful gravel, a divider, a plant on each side, and Micro Whisper filter, and a light in the top. The temperature here is 68 on winter days and 65 on winter nights, and warmer in the summer. I got one at a pet store and one a flea market. Any suggestions would be welcome because I don't want them to die, they are so pretty and interesting to watch!